This invention relates to an optical connector for making an optical connection underwater or in a wet environment.
Optical fibres are frequently used for communication purposes, and it is often necessary to form an optical connection between the ends of such fibres. This generally involves bringing together two connector components each supporting a respective fibre and making end-to-end contact between the fibres. In the case of underwater connectors, it is known to provide the connector components with end sealing arrangements so that the optical fibre ends are protected from the outside environment when the components are in a disconnected state, the end sealing arrangements opening up during connection to allow passage of one of the optical fibre ends therethrough in order to establish the optical connection.
It has been proposed for example in U.S. Pat. No. 4,887,883 to provide the two connector components of an underwater optical fibre connector with end sealing arrangements each comprising a relatively thick (in the axial direction) seal member with an axial opening formed therethrough. The axial openings are kept closed by the resilience of the seal members when the components are disconnected, and during connection a wand structure supporting an optical fibre pushes its way through the mating seal members of the two components. The axially directed optical end face of the optical fibre then makes contact with the end face of the optical fibre in the other connector component. However, with such an arrangement there is a risk of damage to the optical end faces of the optical fibres caused by particles of sand, silt or the like which have lodged on the seal members. Such particles may be transferred on to the end face of the wand supported optical fibre as it forces its way through the seal members and may be carried forward and sandwiched between that end face and the end face of the other optical fibre.
Another arrangement using the idea of sealed chambers which open up during mating to enable an optical connection to be made between axially directed end faces of optical fibres is disclosed in WO-A-9 622 554. During connection, the end of a wand supporting an optical fibre in one connector component exits a chamber of that component and enters a chamber in the other component. In this arrangement, instead of having resilient seal members with axial openings which have to be forced open by the wand, each connector component has a laterally movable gate for opening up the respective chamber during mating. During connection, the movable gate of the chamber housing the wand end opens first, the wand end passes through a region containing ambient water, and the movable gate of the other chamber opens to allow entry of the wand. The wand then passes axially along an oil-filled tube of about the same diameter as the wand, forcing oil out of the tube via a side vent, until end-to-end engagement is made between the respective optical fibres. With such an arrangement, if the ambient water contains debris such as sand, silt or the like, then there is again a risk that particles of debris will lodge against the end face of the wand supported optical fibre and then be carried forward along the oil-filled tube to be sandwiched between that end face and the end face of the other optical fibre. Further, the mechanism and sealing arrangement is complex which is not desirable in subsea operations.
Alternative underwater optical connectors have been proposed in WO-A-8 500 899 and GB-A-2 166 261 having laterally facing optical end faces rather than axially directed end faces. In these arrangements a probe belonging to a male connector component is arranged to push back a stopper piston of a female connector component to enable a laterally facing optical end face on the probe to form an optical coupling with a laterally facing optical end face in the female connector component. In the disconnected condition, the optical end face of the probe is covered by a sleeve. During connection, the sleeve slides back axially along the probe, during which action a wiper passes over the optical end face to wipe it. Similarly, a wiper on the stopper piston wipes the optical end face in the female connector component as the stopper piston is pushed back. Although these known proposals avoid the problem of debris becoming lodged on an axial end face of an optical member when it emerges from its housing, they rely on the effectiveness of the wiping action, and if the wipers deteriorate with time the optical coupling may become contaminated. Moreover, in the connected condition of the connector, the region where the optical coupling is made is not sealed from the outside and may therefore be subject to entry of contaminants.
Another optical connector has been proposed in WO 98/45899, in which the use of axially directed end faces of the optical components to be connected is avoided. In this arrangement a female connector component has a plurality of optical contacts arranged in an annular chamber in a housing, at circumferential intervals around the outside of a retractable cover sleeve, and pointing inwardly towards the cover sleeve. A male connector component has an axially centrally arranged pusher member, also provided with a retractable cover sleeve. A plurality of flexible tubes holding optical fibres are supported at circumferential intervals around the outside of the rear of the pusher member and project forwardly in cantilever fashion. The flexible tubes extend radially outwardly as well as forwardly in such a way that their own resilience urges them against the inside of the cover sleeve. When the male and female connector components are to be mated, a seal ring on the pusher member engages the cover sleeve of the female connector component, whilst a seal ring on the housing of the female connector component engages the cover sleeve of the male connector component. With further axial interengagement, the pusher member pushes the female cover sleeve rearwardly to retract it, and the female housing pushes the male cover sleeve rearwardly to retract that sleeve. Eventually, the annular chamber where the optical contacts of the female connector component are housed is joined with the region where the cantilevering flexible tubes of the male connector component are supported. The flexible tubes are released from being held down by the male cover sleeve and splay outwardly into internal guide grooves in the female housing. Optical contacts at the ends of the flexible tubes then complete optical circuits with the optical contacts of the female component.